Painting Brush

ABSTRACT

The chemical-fiber-made brush is capable of providing sufficient amounts of coating material picked up and released to improve the working efficiency of the coating operation. The brush is provided with bristles  1  made up of a bundle of chemical-fiber monofilaments including wavy monofilaments. By mixing wavy monofilaments and non-wavy monofilaments, the amount picked up can be increased as compared with the case of bristles made up of non-wavy monofilaments, and the spreading out of the leading ends of the bristles can be prevented as compared with bristles made up of wavy monofilaments alone.

BACKGROUND OF THE INVENTION

This invention relates to a painting brush used for applying a coating material.

DESCRIPTION OF THE RELATED ART

Typically, conventional painting brushes use as their bristles chemical fiber monofilaments outstanding in quality, stability of supply and the like. Such conventional brushes using chemical fibers have bristles made up of straight monofilaments alone.

However, the conventional brush having straight bristles alone as described above can pick up and hold only a small amount of coating material. This may be the reason that, in the straight bristles, the monofilaments come into close contact with each other and so reduce the space for holding the coating material between monofilaments.

In such a brush, a small amount of the coating material picked up naturally results in a reduced amount of release, which in turn gives rise to the need of repeatedly dipping the brush into the coating material many times for applying the coating material to the one area. In consequence, the problem of extremely inferior working efficiency arises.

The brush disclosed in Japanese Unexamined Utility Model 6-7983 is known as a brush that overcomes this problem. This conventional brush has straight bristles each having recesses formed in its surface so that the coating material is held in the recesses to increase the amount picked up.

However, the formation of the recesses in the surface of the straight bristles cannot allow a satisfactory amount of the coating material to be picked up. This is because, since a monofilament is naturally thin, even if recesses are formed in such a thin monofilament, the space created by the recesses is not as much as expected, resulting in less of an increase in the amount of coating material held in each monofilament. In either case, the conventional painting brushes having straight bristles alone have the problem of the incapability of ensuring that a sufficient amount of coating material will be picked up.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a painting brush capable of maintaining excellent bundling of bristles, of ensuring that a satisfactory amount of coating material will be picked up and held and a satisfactory amount released, and of offering outstanding working efficiency in the coating operation.

A painting brush having bristles according to the present invention is characterized in tat the bristles comprise straight chemical-fiber monofilaments and wavy chemical-fiber monofilaments.

In the paining brush of the present invention, the wavy monofilaments are included among the bristles in a mixing-proportion of from 10% to 80%.

In the painting brush of the present invention, the bristles include the straight chemical-fiber monofilaments, the wavy chemical-fiber monofilaments and animal hair.

According to the present invention, the mixing of straight monofilaments and wavy monofilaments makes it possible to increase the amount of coating material picked up while maintaining excellent bundling of bristles. As the amount of coating material picked up increases in this manner, the amount of coating material released increases, resulting in improvement in working efficiency of the coating operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged view of a wavy monofilament.

FIG. 2 is a table showing the monofilament dimensions and the mixing proportion for each experimental brush in the present invention.

FIG. 3 is a front view of a printing brush.

FIG. 4 is a table showing the results of experiment 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A painting brush according to an embodiment of the present invention will be described below with reference to the accompanying drawings. The painting brush is provided with a bundle of bristles made up of a mixture of straight monofilaments of chemical fiber and wavy monofilaments of chemical fiber.

For example, polybutylene terephthalate (PBT) can be used to form the monofilaments for the bristles. The type of resin can be selected with reference to the firmness or the like required for the use of the brush. When the brush is fabricated for applying a water-based coating material, almost all resins can be used. However, when the brush is fabricated for applying an oil-based coating material including a solvent, the available resins are limited to those unaffected by the solvent.

The wavy filaments in this embodiment means filaments formed in wavy configuration as illustrated in FIG. 1. For forming the wavy monofilaments, straight monofilaments of chemical fiber are clamped between a pair of wavy members at a temperature at which the clamped monofilament becomes soft to some degree. The wavy monofilaments thus obtained and the straight monofilaments are mixed together to form the bristles 1 shown in FIG. 3.

EXPERIMENT EXAMPLES

Experiments were conducted on the bristles 1 made up of a mixture of the straight monofilaments and the wavy monofilaments as described above.

In the experiments, PBT-made straight monofilaments and PBT-made wavy monofilaments as illustrated in FIG. 1, which form the bristles 1, are used to fabricate experimental brushes No. 1 to No. 4 shown in the table in FIG. 2. The table in FIG. 2 shows the diameter and the length of each monofilament used in experimental brushes No. 1 to No. 4 and the proportion of the mixing of each monofilament.

In the “monofilament configuration” column of the table in FIG. 2, the configuration of the wavy monofilament subjected to the waving process is designated as “wavy” and the configuration of the straight monofilament is designated as “straight”.

As seen from the “diameter” column, all the wavy monofilaments used in each experimental brush have a diameter of 0.1 mm, and the straight monofilaments used in each experimental brush are of two types of diameters, 0.1 mm and 0.125 mm. The reason for mixing in of 0.125-mm-diameter straight monofilaments is to provide a high firmness for the bristles 1.

The wavy monofilaments and the straight monofilaments as described above were mixed in the mixing-proportions shown in the table in FIG. 2 to form the bristles 1 of each of the experimental brushes No. 1 to No. 4.

The amount of monofilaments used for each bundle of bristles 1 was determined such that the experimental brushes No. 1 to No. 4 were identical in the size of the bundle of the bristles 1.

The length shown in FIG. 2 means the length of the monofilaments forming the bristles. As shown in FIG. 2, each of the experimental brushes No. 1 to No. 4 uses a combination of monofilaments of different length. In this manner, the monofilaments of different length are combined to form the bristles 1 in order to prevent the leading ends of the monofilaments from spreading out, to ensure improved bundling of the bundle of bristles.

A handle 2 is attached to the bristles 1 thus fabricated to form a brush as shown in FIG. 3. The bristles 1 thus fabricated have a leading-end width W2 greater than the handle-end width W1.

Then, the experimental brushes No. 1 to No. 4 and a conventional brush are dipped into a water-based coating material and the amount picked up and the amount released are measured for each brush. FIG. 4 shows the results of the measurements. The amount picked up means the weight of the coating material held in the bristles when the bristles are dipped in the coating material under certain conditions. The amount released means the weight of the coating material released from the bristles onto the coated face when the coating material held in the bristles is applied to the face to be coated. The amount picked up and the amount released are measured by the change in the weight of the brush.

The conventional brush has a bundle of bristles made up of PBT-made straight monofilaments alone. The thickness and the length of the bundle of bristles of the conventional brush are the same as those of the experimental brush No. 2.

As seen from the comparison between the experimental brushes and the above-described conventional brush shown in the table in FIG. 4, the amount picked up and the amount released are greater in the experimental brushes No. 1 to No. 4 than in the conventional brash. In particular, the fact that the amount released is large means that a wide area is coated by the brush dipped only one time in the coating material. Accordingly, the use of the brush of the embodiment makes it possible to reduce the number of dips of the brush in the coating material as compared with the use of the conventional brush to improve the working efficiency in coating.

As described above, it can be judged that the reason why the amount picked up of the experimental brushes No. 1 to No. 4 is greater than that of the conventional brush is that the waves of the wavy monofilament create gaps in the bristles suitable for holding the coating material and the coating material is held in the gaps.

It can therefore be judged that the reason why the amount released of the experimental brushes No. 1 to No. 4 is greater than that of the conventional brush is that a large amount picked up causes an increase in the amount released.

As seen from the results in FIG. 4, the experimental brush No. 4 with the highest mixing proportion, 50%) of the wavy monofilaments shows an increase in the amount picked up and the amount released. It can be judged from this that as the proportion of wavy monofilaments is increased, the volume of the gaps between the monofilaments is increased, thus increasing the amount of coating material held in the gaps, in turn increasing the amount picked up.

The higher the proportion of the wavy monofilaments, the more the leading ends of the bristles are spread out. In contrast, the higher the proportion of the straight monofilaments, the more the spreading out of the bristles is effectively prevented, so as to improve the bundling. The spreading out of the leading ends of the bristles may make the coating operation difficult. For example, when the coating material is applied to an area close to the boundary between two coated areas exactly along the boundary, the spreading bristles are apt to cross the boundary, resulting in the coated face extending beyond the boundary. In this manner, a brush with bristles with the spreading leading-ends is hard to use. However, when the coating material is applied quickly to a wide area, a brush with the spreading leading-ends is useful.

Thus, the mixing-proportion of the wavy monofilaments is desirably adjusted in accordance with the intended use.

In actually, the most suitable mixing-proportion of the wavy monofilaments varies with the viscosity, the surface tension and the like of the coating material used, but, in the case of it being more than 80%, the leading end of the bristles may possibly spread out too much, leading to inferior working efficiency. On the other hand, when the amount of wavy monofilaments is below 10%, the amount picked up notably decreases, thus giving rise to the need for repeatedly dipping the brush in the coating material many times to coat the area. Accordingly, it is understood that a suitable condition is a mixing-proportion of wavy monofilaments ranging from 10% to 80%.

In addition, irrespective of the use of wavy monofilaments, the spreading out of the bristles is prevented because the bristles include straight monofilaments.

Further, regard to the bristles made up of a mixture of wavy monofilaments and straight monofilaments as in the experimental brushes No. 1 to No. 4, if the mixing-proportion of the straight filaments is decreased and animal hair is added instead, in other words, if wavy monofilaments, straight filaments and animal hair are mixed together, this makes it possible to further increase the amount picked up of the coating material.

For example, half the straight monofilaments of a diameter of 1 mm and a length of 65 mm of the experimental brush No. 1 are replaced with animal hair to constitute bristles including 20% of animal hair. These bristles increase the amount picked up by 20% or more over that of the experimental brush No. 1, resulting in an increase in the amount released. This is because the animal hair has cuticles on its surface and therefore can hold the coating material.

The bristles including animal hair basically have the advantage of a large amount picked up of the coating material, but also the disadvantage of sticking together caused by the water-based coating material. However, the animal hair is mixed and bound together with the chemical-fiber straight monofilaments and wavy monofilaments, whereby the animal hairs are able to be kept out of contact with each other to prevent the resin from making the animal hairs stick together. For this reason, animal hair can be used for a water-based coating material.

However, if the proportion of animal hair included in the bristles exceeds 50%, the animal hairs may possibly be stuck together for a short time period by the coating material. Therefore, the desirable proportion of animal hair is equal to or less than 50%. 

1. A painting brush having bristles, wherein the bristles comprise straight chemical-fiber monofilaments and wavy chemical-fiber monofilaments.
 2. A painting brush according to claim 1, wherein the wavy monofilaments are included among the bristles in a mixing-proportion of from 10% to 80%.
 3. A painting brush according to claim 1, wherein the bristles include the straight chemical-fiber monofilaments, the wavy chemical-fiber monofilaments and animal hair. 